Shruthi Aradhya, Prakash Reddy, Shylaja Ramlal, Sowmya Nagaraj, Bhairab Mondal and Harishchandra Sripathy Murali*

Department of Microbiology, Defence Food Research Laboratory, Mysore, India.

Abstract

Diarrheagenic Escherichia coli, an important etiologic agent of diarrhea is a major public health problem in developing countries, particularly in children. Enteropathogenic Escherichia coli is a leading cause of infantile diarrhea. Although the frequency of these organisms has decreased, they continue to be an important cause of diarrhea. Therefore, in the present study, a sensitive and specific IgY mediated Immunocapture-PCR (IC-PCR) was developed for the detection of enteropathogenic E. coli (EPEC). Due to an advantage of avian immunoglobulin (IgY) to have the least affinity towards staphylococcal enterotoxin A (SpA) responsible for false positives, we employed anti- outer-membrane protein (OMP) IgY generated in chicken for capture of bfpA gene and was incorporated with PCR amplification. In the present study, IgY mediated immunocapture of bfpA gene was free from false positives due to protein A, a common drawback in IgG mediated immunocapture techniques. Furthermore, spiking studies and analysis on natural samples emphasized the robustness as well as applicability of developed method. The developed assay could be reliable in the detection of EPEC as a routine investigation method. Further, the assay could be further applied for the detection of other pathotypes from food and clinical sources.

Keywords: EPEC, Immunoglobulin Y, Staphylococcal protein A, Immunocapture-PCR, E. coli, Diarrheagenic E. coli.